You do take your chances with a salvage yard transmission. They usually have a 30 day return policy if it is bad, but it's still a PIA to return it and pull another trany (if they have one). A couple of things you can check before pulling a used trany is the drain plug which has a magnet built in. If the magnet has pieces of bearings or gear teeth stuck to it, walk away. Once the trany is out of the car, turn the input shaft by hand in each of gears and be sure it is nice and smooth. I just pulled an 83 ZX 5-speed two weeks ago at an Omaha U-Pull yard. Only cost $60 there . I later found it had a weak 3rd gear syncro so I pulled it apart and swapped it with parts from another 5-speed I had laying around. Working good now.